DESCRIPTION: The U.S. elderly population is projected to grow significantly in the future, in part, due to increasing life expectancy at later ages, and in part, due to the passing of age 65, from 2011 to 2028, by the large cohorts born after WWII. The investigators will examine the effects of those cohorts and the cohorts born immediately before and after them, on Medicare and other projections of health service needs. The investigators will examine projections not only for the period when the cohorts first pass age 65 but also for subsequent periods during which they will age, have health needs increase, and then start to die more rapidly out of federal and other health programs. Thus, the investigators will examine health, and health service, projections, for the entire period 1997 to 2070 - a period that covers the range of most current health services projections. The investigators will evaluate the impact of improved education, income, and the different health experiences of post-WWII birth cohorts. This requires using biologically motivated population forecasting models developed earlier in this project to predict health service needs -- a natural extension of the models because they were designed to model health changes in elderly populations to improve mortality and population projections. This extension of their health forecasting models to project health service needs is important because current actuarial/demographic models of, e.g., the Medicare program a) treat health as a latent variable, and b) do not anticipate effects of new biomedical technologies and therapies of health service use. In evaluating forecasts of future health service needs the investigators will examine: a) mortality and life expectancy assumptions, b) projected changes in chronic disability and morbidity, c) effects of technological innovations on health trends, d) the relation of health changes to health care productivity, e) backward projections of current health service projections to examine health changes implicit in existing Medicre projections, f) implications for estimating program burden using different support ratios, g) effects of mortality changes on future age specific health needs and costs, and h) changes in types of services used.